The invention relates to a dental handpiece with a headpiece for receiving a treatment tool, a handgrip for manipulating the handpiece having a forward end to which the headpiece is attached, and a lighting means with an incandescent lamp arranged in the forward region of the handgrip. The longitudinal axis of the incandescent lamp is orientated substantially parallel to the longitudinal axis of the forward region of the handgrip, and laterally adjacent to the incandescent lamp there is provided a light outlet in the handgrip.
With conventional dental handpieces, the light sources are mostly arranged in the rear region of the handpiece and the light is conducted to the forward end of the handpiece by means of optical fibres. Such handpieces have the disadvantage that when the light is fed into the optical fibres, and when the light is transmitted, there are losses in light intensity. Moreover, when optical fibres are used, there is the difficulty of orientating their light-emitting ends in a suitable manner in the direction of the place being treated. Because of their fragility, they can only be slightly bent, and the angle of bending permissible is generally insufficient to orientate their ends precisely onto the place being treated.
A handpiece without light conduction is known from AT-PS 384 546. In the forward part of the handgrip for this handpiece an incandescent lamp is arranged, and the light emitted by this incandescent lamp is deflected by an optical element in front of the incandescent lamp, in the form of a prism or mirror, in the direction of the place being treated. The low light yield is disadvantageous, because only a small region of the solid angle of the light radiated from the incandescent lamp actually reaches the place being treated. The prism used causes further light losses.
A handpiece of the type described in the introduction is known from U.S. Pat. No. 4,711,630. In contrast to AT-PS 384 546, the incandescent lamp is arranged still further forward, and a part of the light emitted by it reaches the place being treated directly by means of a slit-shaped light outlet arranged laterally adjacent to the incandescent lamp in the handgrip. A further part of the light emitted by the incandescent lamp is conducted by means of a lens at the forward end of the incandescent lamp and optical fibres in the headpiece, and from there is likewise radiated in the direction of the place being treated. In this way, although the light yield is increased compared to the handpiece of AT-PS 384 546, nevertheless the construction is complex, and therefore expensive. The space needed for the optical fibres in the headpiece is also disadvantageous, and makes it larger. Thus, the whole handpiece becomes less manageable.